CH121 Soil Characterisation Site data sheet DEWNR Soil and Land Program
ACIDIC SANDY LOAM OVER RED CLAY ON ROCK General Description: Hard massive and gravelly acidic sandy loam abruptly overlying a
coarsely structured red clay forming in micaceous basement rock
Landform: Upper slopes of undulating to rolling low hills
Substrate: Micaceous basement rock, mainly schists and phyllites
Vegetation: Blue gum woodland
Type Site: Site No.: CH121 1:50,000 mapsheet: 6628-2 (Onkaparinga)
Hundred: Talunga Easting: 316500
Section: 123 Northing: 6148950
Sampling date: 28/08/99 Annual rainfall: 740 mm average
Upper slope in rolling low hills. Firm surface with occasional surface ironstone and quartz stones and 14% slope.
Soil Description:
Depth (cm) Description
0-10 Dark brown firm sandy loam with weak granular structure and 2-10% quartz grit. Clear to:
10-25 Reddish brown (bleached when dry) massive light sandy loam with 10-20% quartz gravel and grit. Abrupt to:
25-50 Red hard medium clay with coarse subangular blocky structure breaking to medium angular blocky. Diffuse to:
50-75 Red, orange and reddish yellow firm silty light clay with weak coarse lenticular structure and 20- 50% soft weathering phyllite. Diffuse to:
75-100 Red and orange firm silty light clay with weak coarse lenticular structure and more than 50% soft weathering phyllite. Gradual to:
100-150 Weathering phyllite.
Classification: Bleached, Mesotrophic, Red Chromosol; medium, slightly gravelly, loamy / clayey, deep
CH121 Soil Characterisation Site data sheet DEWNR Soil and Land Program
Summary of Properties
Drainage: Well drained. Water will perch on the clay, but saturation is unlikely to last for more than a day or so.
Fertility : Natural fertility is low (as indicated by the low exchangeable cation values in subsoil). However, surface nutrient retention capacity is high due to favourable organic matter levels. Data suggest possible copper deficiency.
pH: Acidic throughout, but not strongly so. Periodic liming is required.
Rooting depth: Good root growth to 100 cm.
Barriers to root growth:
Physical: Firm coarsely structured clayey subsoil restricts even root proliferation.
Chemical: High aluminium in 10-25 cm layer (lime required).
Waterholding capacity: Approximately 130 mm in rootzone (high).
Seedling emergence: Good, provided that surface condition is maintained (high organic carbon levels).
Reduction in organic matter will lead to hard setting.
Workability: Good.
Erosion Potential:
Water: Moderately high due to the slope of the land.
Wind: Low.
Laboratory Data
Trace Elements mg/kg (EDTA)
Exchangeable Cations cmol(+)/kg Depth
cm pH H2O
pH CaC12
CO3
% EC1:5
dS/m ECe dS/m
Org.C
% Avail.
P mg/kg
Avail.
K mg/kg
SO4
mg/kg Boron mg/kg
Cu Fe Mn Zn CEC cmol (+)/kg
Ca Mg Na K
ESP Exch Al mg/kg
Paddock 6.3 5.5 0 0.08 - 3.4 39 236 15 1.2 0.90 206 18 2.16 9.6 8.1 1.2 <0.1 0.35 <1 -
0-10 6.4 5.6 0 0.07 - 3.9 20 204 9.4 1.2 0.96 147 18 2.4 11.5 9.7 1.4 <0.1 0.31 <1 - 10-25 5.9 4.8 0 0.03 - 0.9 6 131 3.0 0.8 0.37 57 2.8 0.34 4.8 2.4 0.57 <0.1 0.13 na 10.3 25-50 6.0 5.0 0 0.04 - 0.5 2 270 2.9 1.0 0.17 90 0.48 0.17 5.8 2.8 1.0 0.11 0.43 1.9 0.9 50-75 6.3 5.4 0 0.05 - 0.4 3 184 5.7 0.8 0.21 29 0.36 01.5 5.7 2.3 1.8 0.14 0.23 2.5 - 75-100 6.4 5.5 0 0.05 - 0.3 3 139 10.8 0.8 0.24 24 0.41 0.16 4.5 1.8 1.9 0.15 0.11 3.3 -
Note: Paddock sample bulked from 20 cores (0-10 cm) taken around the pit.
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Further information: DEWNR Soil and Land Program
